Orthopter



June 15, 1943. c. G. BOQATRIGHT 2,321,

.ORTHQPTER Filed Nov. 27, 1939 I 2 Sheets-Sheet '1 INVENTOR CLYDE G. BOATR/GHT ATTORNEY.

June 15, 1943.

c. ca. BOATRIGHT ORTHOPTER Filed Nov. 27. 1939 2 Sheets-Sheet 2' 1N VENTOR. CL YDE 6: 50A TR/GHT ATTORNEY.

Patented June 15, 1943 UNITED STATES PATENT OFFICE ORTHOPTER Clyde G. Boatright, San Pedro, Calif. Application November 27, 1939, Serial No. 306,310

(Cl. 4l6-74) 7 Claims.

This invention relates to. orthopters, or flying machines adapted to be sustained and propelle in flight by flapping wings.

An object of my invention is to provide a flying machine of the general class indicated, which is particularly adapted to embodiment in a model, or toy, flying machine, because of its capability of being produced in large numbers at an absolute minimum of cost and assembled into a small model aircraft rapidly and cheaply by relatively unskilled persons. 7

Another object in this connection is to provide a flying machine as described, which, while being suspectible of production at low cost and in large quantities, is capable of flight over distances long enough and for a sufficiently long period of time to cause the device to have great appeal, and accordingly a high sale value, among youths and others interested in flying model airplanes, whether for the purpose of amusement or for scientifically studying principles of flight.

A further object of my invention is the provi sion of an orthopter of the character described, which is possessed of principles of construction and which is formed in such a manner and of materials so light, that it is capable of being propelled in flight by power derived from a twisted rubber band.

Another object is to provide a model aircraft as described which, when not in use, can be folded flat, thus enabling it to be stored and shipped, either singly or in quantity, with the utmost convenience.

Yet another object is the provision of a model orthopter of light, inexpensive form, as indicated, which also is sufficiently rugged and durable to withstand a reasonable amount of abuse, such as the shocks of alighting after flight.

A further object of my invention is to provide a toy or model aircraft which closely resembles a bat, both in appearance and in manner of flight, a feature which adds materially to the appeal of the article, because of the amusing appearance presented by the device while flying.

The invention posssesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred embodiment of the invention illustrated in the drawings accompanying and forming a part of the specification. It is to be understood that I do not limit myself to the showing made bythe said drawings and description, as I may adopt variations of the preferred form within the scope of the invention as set forth in the claims.

Referring to the drawings:

Figure l. is a top plan view of an orthopter constructed in accordance with the principles of the present invention.

Figure 2 is a front elevation, the direction of view being indicated by the arrow 2 of Fig. 1. The position assumed by the wings of the device when at the upper extreme of their movement is indicated in broken lines.

Figure 3 is an enlarged perspective view of the framework of the device before the wing material has beenattached thereto. Portions of the flgure have been broken away to reduce its size.

Figure a is a detail view in perspective, showing the manner of connecting each of the wing ribs to its associated spar.

Figure 5 is a vertical sectional view taken longitudinally of the orthopter along the line 5-5 of Fig. 1 with the direction of view as indicated.

In terms of broad inclusion, the device of the present invention is a flying machine of the orthopter type, in that it is adapted tofly through the air through the expedient of flapping wings. The wings are mounted for flapping movement, upon a central frame which carries the motor for oscillating the wings; and flight control is established by means of structural details of the wings, thereby obviating the necessity of providing vertical and horizontal rudders of the type employed in more conventionally constructed aircraft.

More specifically described, the orthopter of my invention is illustrated in the drawings as being embodied in a model aircraft intended for use as a toy or for the purposes of scientific investigation and experimentation. It is to be understood, however, that I do not wish to be limited in the utilization of the novel features of construction herein disclosed and claimed, to their embodiment in model aircraft, for the reason that they are susceptible of being advantageously incorporated in full size, commercial aircraft, where the same principles of flight and flight control may be relied upon as in the case of the model aircraft here chosen for the purpose of illustration and description.

In the present modification, the central frame 6 of the model orthopter comprises a wire bent to U-shape, to provide a pair of legs "I and. 8 held in spaced, parallel relation by an interconnecting portion 9 of the wire. The wire frame thus presented is disposed in inverted position, i. e., with the legs I and 8 extending vertically downwards from the front and rear ends, respectively, of the interconnecting portion 9, which thus becomes the top member of the frame 6. The lower ends of the legs 1 and 8 are interconnected by a strut il constructed of suitable material to withstand the compressive and torsional stresses imposed thereupon by the motor l2, for which it serves as the support, balsa having been found advantageous for this purpose because of its great strength coupled with its relative lightness.

In the present modification, the motor l2 takes the formlof an elastic band l3, under tension between a crankshaft l4 and an anchorim hractu et i6 at the front and rear ends, respectively, of the spar H. The crankshaft [4 comprises a suitable length of sufliciently stiff wire bent to provide a crank pin I! connected to the journalled portion [8 by a crank throw [9, and a hook 2| at the after end of the journalled portion 18 which is open so as to facilitate mounting of the rubber band 13 thereupon. pin H, a handle 22 is provided, being connected to the crank pin I! by a longer throw portion 23, disposing the handle at such a distance from the axis of rotation of the crankshaft l4 that the manual turning of the crankshaft, and consequent twisting of the rubber band [3, is facilitated.

The crankshaft M is journalled in a suitable bearing 26 at the lower end of a bracket 21 extending downward from the forward end of the strut H. The bracket 21 is carried by a tubular sleeve 28 fitting upon the strut, and an upwardly extending sleeve 29 rigid with the sleeve 28 receives the lower end of the forward leg 1 of the frame 6.

The frame 6 also serves to mount the wings 3|,

two of which are provided, extending to opposite Means are provided for pivotally attaching the inner ends of the spars 32 to the top member 9 of the frame 6. the member 9 adjacent the forward end thereof, and has a pair of lateral extensions 3'! upon each side thereof. Each of these pair of extensions provides fore and aft bearings for a pintle 38, the forward end 39 of which is bent to extend along the associated spar 32, to which it is firmly secured as by a pair of clamps 4 I. At its outer end, each of these lateral extensions 39 is bent forward to provide a pin 42; and upon each of these pins 32 the upper end of a connecting rod 43 is journalled. The lower ends of both of these connecting rods 43 are revolubly mounted upon the crank pin H, with the result that when the crankshaft i4 revolves, the wing spars 32, due to their interconnection to the eccentrioally disposed crank pin ll, are caused to oscillate up and down about the respective axes of their pivotal mounting upon the frame 5.

As a matter of convenience, it is preferred that the wing covering 34 for both wings 3| be formed of a single strip of material extending all the way across the device from wing tip to wing tip. In form, the wings resemble those of a bat, in that each of the wings 3| is relieved at its after, outer corner, as indicated at 45. Accordingly, each of the wings 3! is considerably wider (measured longitudinally of the orthopter) amidships than adjacent the outer extremity of the wing. The wider portions 4! of the wings thus provided arejoined together, i. e., are continuous across the frame 6. Hence they co-operate with each other and with the other portions of the wing structure to define an airfoil area corresponding in function to the stabilizer and elevator rudder of a conventional airplane. Toward this same end, the after edge 48 of the wider portion 41 of the wings curves upward slightly, as best shown,

A bracket 36 is fastened upon Forward of the crank structure in this form, inasmuch as they curve upward similarly at their after ends, and they are attached to the wing covering material throughout their entire length, any suitable adhesive, such as the bonding material known in the trade as airplane dope being used for this purpose. Since the stiffening of the inboard, wider portion 4'! of the wing structure is of greater importance than adjacent the extremities of the wings, I have found it advantageous to dispose the ribs 33 closer together amidships, as clearly shown on Fig. 1.

Whereas the wing covering material 34 is preferably attached to the upper portion 9 of the wire frame 6, as by a strip 49 of tape, one of the details of construction of the device of the present invention which is a contributing factor in its ability to fly, is the flexibility of the Wing structures, particularly their after portions, and their freedom of up and down movement with respect to the leading edges of the wings. Except for being attached amidsliips to the upper member 9 of the wire frame, the wings are supported along their leading edges, only, i. e., by the spars 32. There being no laterally extending frame members (corresponding to the spars 32) associated with any portion of the wings other than the leading edges, the wing covering material is left relatively slack; and this feature, coupled with the fact that the rib-s 33 are connected to the spars 32 for pivotal movement, permits the wing structures to flex as they are moved up and down, in such a manner that the after edges of the wings lag behind the leading edges. Hence, as the wings move downward, the wings slope upwards toward the rear; and when the wings move upward, the wings slope downward toward the rear. This results in the development of a thrust by the wings against the air, causing the craft to move forward at a rate determined by the rate of flapping of the wings and by the amplitude of their stroke.

As stated, the after edges 48 of the wider portions of the wings are deflected upwards, with the result that they act as elevators, causing the craft to nose upwards as it moves forwards through the air. Accordingly, the device is enabled to gain and maintain altitude, depending, of course, upon the extent to which the elastic band I3 is tensioned, and the consequent rate of flapping of the wings.

Whereas any convenient means for pivotally attaching the ribs 33 to the spars 32 may be employed, I have found it most expedient to utilize the method illustrated in the drawings, and shown to best advantage on Fig. 4. Inspection of this figure will reveal that the ribs 33 do not quite touch the spars, but have their forward ends spaced slightly therefrom, say a quarter or an eighth of an inch. Since the covering material 34 is adhesivelybonded to both the spars and the ribs, the-covering material itself contributes to the proper support of the ribs upon the spars; but, in order. to reinforce the interconnection between each rib and its associated spar, I prefer to wrap a strip 5| of suitable flexible tape around the spar at the point where a rib or ribs are to be connected thereto, with the ends of the tape extending back to embrace the forward end of the rib therebetween. If gummed tape be employed for this purpose, the problem of assembly is materially facilitated.

Another detail of importance is best understood by reference to Figure 4. It should be observed that the wing covering material 34 is fastened to the under surface of each of the spars 32, instead of to the upper edge. Because of this arrangement, a slight concavity 52 is presented in the upper surface of each wing 3|, just aft of the extreme forward, or leading edge thereof. It is believed that this aids in the development of a partial vacuum immediately above the wings, thus adding to the lift that the device develops as the wings oscillate.

Preferably the ribs 53 adjacent the ends of the wings are grouped in such a manner that several radiate from a single point of attachment to the associated spar. This arrangement has been found to make the outer ends of the wings more flexible than if the ribs are all kept parallel, particularly if the spars are slightly shorter than the wings, leaving a short portion 54 of each wing extending outwards beyond the outer end of the associated spar and accordingly supported only by the flexibly mounted and angularly extendin outer stiffening ribs 53.

I claim:

1. In an orthopter of the character described, a center frame, spars pivoted to said frame adjacent the forward end thereof and extending laterally therefrom, a wing affixed along its forward ed to each of said spars, each of said wings being of flexible material and extending aft from its associated spar, a plurality of reinforcing ribs afiixed to each of said wings and extending aft from adjacent the associated spar, flexible means connecting each of said ribs to the associated spar permitting the after ends of said ribs and the after edges of said wings to trail the forward edges of the wings as said wings move vertically, and means for oscillating said wings up and down to develop a flapping motion of said wings.

2. In an orthopter of the character described, a longitudinal frame, spars pivoted to said frame and extending laterally therefrom, a wing carried by each of said spars and afiixed thereto along the forward edge of the wing, said wings being of flexible material and interconnected to present an airfoil continuous across said orthopter from wing tip to wing tip, and said wings being substantially bat wing shaped to present an airfoil materally wider amidships than adjacent their outer ends andthe wider portion of said wings being disposed at the rear thereof to present a horizontal tail fin for said orthopter integral with thewing structure thereof, and means for oscillating said wings in a flapping motion.

3. In an orthopter of the character described, a longitudinal frame, spars pivoted to said frame and extending laterally therefrom, a wing carried by each of said spars and affixed thereto along the forward edge of the wing, said wings being of flexible material and interconnected to present an airfoil continuous across said orthopter from wing tip to wing tip, and said Wings being substantially bat wing shaped to present an airfoil materially wider amidships of said wings than adjacent the outer ends thereof, stiffening means associated with said wider portion of said airfoil and deflecting the after edge thereof upward, and thereby present a stabilizing air foil formed as a portion of the structure of said wings and means for oscillating said wings.

4. In an orthopter of the character described, a longitudinal frame, spars pivoted to said frame and extending laterally therefrom, a wing carried by each of said spars and affixed thereto along the forward edge of the wing, said wings being of flexible material and interconnected to present an airfoil continuous across said orthopter from wing tip to wing tip, and said wings being substantially bat wing shaped to present an airfoil materially wider at the inboard portion of said wings than adjacent their ends, means extending longitudinally of said orthopter for imparting relative rigidity to said wings, said stiffening means curving said wings upward along their after edges to provide an elevator for said orthopter, and means for oscillating said wings.

5. In. an orthopter of the character described, a longitudinal frame, spars pivoted to said frame and extending laterally therefrom, a wing carried by each of said spars and affixed thereto along the forward edge of the wing, said wings being of flexible material and interconnected to present an airfoil continuous across said ortho-p-ter from wing tip to wing tip, and said wings being substantially bat wing shaped to present an airfoil having an inboard portion extending aft from said airfoil, means extending longitudinally of said inboard portion of said airfoil for imparting stiffness thereto, said stiffening means curving the after edge of said inboard portion of said wings upward to provide an elevator for said orthopter, and means for oscillating said wings.

6. In an orthopter of the character described, a longitudinal frame, spars pivoted to said frame and extending laterally therefrom, a wing carried by each of said spars and affixed thereto along the forward edge of the wing, said wings being of flexible material and interconnected to present an airfoil continuous across said orthopter from wing tip to wing tip, and said wings being substantially bat wing shaped to present an airfoil materially narrower adjacent the outer ends of said wings than amidships, stiffening ribs attached to said wings and extending longitudinally of said orthopter, said ribs being closer together amidships of said orthopter than adjacent the outer ends of said wings to impart additional stiffness to the inboard portion of said airfoil, means pivotally attaching the forward ends of each of said ribs to one of said spars, each of said attaching means comprising a strip of flexible material folded around the spar and embracing the forward end of the associated rib, and means for oscillating said wings.

'7. In an orthopter of the character described, a frame, a pair of wings pivoted thereto and extending to opposite sides thereof, each of said wings comprising a spar at the leading edge of the wing and a covering of flexible material extending aft from said spar, said covering material being relatively slack along its after edge and supported along its leading edge only whereby the after edge of each wing is caused to lag after the forward edge as said wings oscillate and dispose the wings in a sloping position to develop a forward thrust upon the orthopter, and means for oscillating said wings comprising a crank journaled on said frame, means for rotating said crank, and a connecting rod connecting each of said wings to said crank, said crank being spaced from said. wings and said connecting rods being of material length whereby said wings are caused to operate out of synchronism.

cums G. eosraicn'r. 

